Romain Grosjean admits he doesn't know why only Kimi Raikkonen has been confirmed as staying with Lotus for 2013.

Raikkonen's contract extension was announced the day after the Indian Grand Prix, but no comment was given on Grosjean's future. When asked if it was because Raikkonen could command enough publicity on his own, Grosjean admitted he was unsure why his own seat has yet to be decided.

"To be honest I have no idea," Grosjean said. "I think with the team we're happy together, they've put a lot of confidence in me and a lot of faith when it was a bit harder time. I showed them that I'm working and improving and trying to work out all the problems we had while still keeping the speed, so there's no reason that it goes bad for the future."

Grosjean also believes that Lotus has missed its best opportunities to win this season as the teams ahead make the use of bigger budgets to outdevelop the team.

"I think we had some good opportunities, for many reasons we didn't manage to get them, but it was not the aim or the objective of the year. We are on our target, we were higher than expectations at one point but now we are where we wanted to be. Yes we are struggling a little bit more at the end of the year whereas McLaren, Ferrari and Red Bull with the big budgets are keeping the development. We do development our car - we don't stop - but as well we are thinking about the future."